The purpose of this study was to evaluate the physicochemical properties and antioxidant activities not only of five types of red peppers, including Tien Tsin pepper(CRP), Korean hot pepper(KRP), Thai pepper(TRP), Bird′s eye chili pepper(VRP), and sweet pepper(SRP), but also of their Kochujang during 90 days of aging periods. The moisture content of all peppers was less than 15 %, and the pH level ranged from 3.97 ~ 4.84. The sugar content had the highest in SRP (7.00 °Brix) and color values, such as L(lightness)-, a(redness)-, and b(yellowness)-values, were also higher in SRP, compared to that of others(p<0.05). The major free amino acids of all samples were aspartate, alanine, and isoleucine, whereas serine and histidine were very low. Among the red peppers, SRP had the highest content of the total free amino acid (1747.41 mg%). Furthermore, SRP showed the highest values not only of antioxidant compounds concentration including total polyphenols, total flavonoids, and vitamin C but also of antioxidant activities by DPPH radicals and ABTS radicals, and, FRAP assay, compared to those of other samples. Capsaicin and β-carotene concentrations were higher in CRP than those of other samples. Based on the analysis of physicochemical properties of Kochujang prepared by each red pepper species, the moisture of all samples showed range of 45.03 % to 48.69 % at the preparation day, and a little increased in the values during 90 days of fermentation periods. The crude ash, crude protein and crude fat were also a little increased for fermentation periods. The pH level of Kochujang prepared by each red pepper species was significantly decreased during fermentation periods, whereas titratable acidity and total acidity were significantly increased in accordance with the fermentation period. The salinity and reducing sugar content of Kochujang prepared by each red pepper species significantly increased in the early fermentation stage and decreased during the late stage. The Kochujang’s L, a, b values fluctuated in accordance with the storage period, but it slightly decreased at the 90th day of fermentation. Viscosity of Kochujang prepared by CRP and SRP increased significantly with fermentation period, but the values of Kochujang prepared by KRP, TRP, and VRP significantly decreased after 75 days. The sugar content of SRP (5.43 ~ 5.97 °Brix) had the highest value, compared to those of others. The free amino acid content increased in all types of Kochujang during fermentation periods. Especially, Kochujang prepared by SRP had the highest free amino acid content level, which ranged from 658.72 ~ 1010.65 mg%. The Kochujang prepared by CRP showed the highest value in total polyphenols (313.30~368.79 mg GAE/100 g) and total flavonoids (8.41~9.43 mg RE/100 g), meanwhile the Kochujang prepared by SRP had the highest in vitamin C content (194.00~292.67 mg/100 g). The Capsaicin content in the Kochujang prepared by CRP, TRP, and VRP were much higher than that in other samples, whereas β-carotene content in the Kochujang prepared by CRP was 4.77 ~ 6.57 mg%, which was the highest. Based on the antioxidant activities by DPPH radical scavenging activity, ABTS radical scavenging activity and FRAP assay, antioxidant level generally increased in the earlier fermentation stage than the later stage. Also, the antioxidant activity of the Kochujang from CRP was the highest at the 90th day of fermentation. .In conclusion, the analysis of the five species of red peppers and Kochujang revealed that the physicochemical and antioxidant properties of Kochujang prepared by CRP and SRP appeared to be superior to that of other samples.